Browsing Reprints by Issue Date
Now showing items 61-80 of 548
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The Strait of Sicily in relation to the general circulation of the Mediterranean
(NATO. SACLANTCEN, 1972/09) -
The hydrological characteristics of the waters exchanged between the eastern and the western basins of the Mediterranean
(NATO. SACLANTCEN, 1972/09)An analysis is done of hydrographic data obtained in 1965 and 1966 in the region of Tunis-Sicily-Malta. Vertical sections permit to follow the opposite spreadings of the surface water of Atlantic origin and the levantine ... -
A contribution to the study of surface and subsurface zooplankton in the Strait of Sicily
(NATO. SACLANTCEN, 1972/09)Analysis of 71 hauls of plankton in the Strait of Sicily, from 2 February to 16 March 1966, enabled us to make a systematic, quantitative and ecological study of all zooplankton systems present. A synthesis was made, from ... -
A contribution to the study of the surface and deep zooplankton in the Strait of Sicily
(NATO. SACLANTCEN, 1972/09)Analysis of 34 hauls of plankton in the Strait of Sicily, from 5 to 21 May 1970, enabled us to make a systematic, quantitative and ecological study of all zooplankton systems present. Vertical fishing was performed with a ... -
The structure of fronts in the seasonal thermocline
(NATO. SACLANTCEN, 1972/09)Some years ago, when the first continuous profiling temperaturesalinity- depth probes came available it was discovered that tht thermocline had a layered structure. The thickness of these layers was a few metres and ... -
A deep stepped thermohaline structure deep in the Mediterranean
(NATO. SACLANTCEN, 1972/09)A deep stepped thermohaline structure has been observed in the Tyrrhenian Sea below the Levant ine water salinity maximum. The layers are remarkably homogeneous starting with a thickness of 10 m - 20 m at 600 m and thereafter ... -
The Maltese oceanic front: a surface description by ship and aircraft
(NATO. SACLANTCEN, 1972/09)Simultaneous observations by ship and aircraft of an oceanic fronta ! zone east of Malta in May 1971 show a predominatly north-south boundary between two water masses evidently formed by surface water from the western ... -
The general geophysics and geology of the Strait of Sicily
(NATO. SACLANTCEN, 1972/09)Available geophysical and geological data combined with newly compiled bathymetric, bottom sample, underwater photograph and recently published geophysical data [Ref. lJ have been analysed to describe the geophysical and ... -
A theoretical model for the backscattering strength of a composite roughness sea-surface
(NATO. SACLANTCEN, 1974/02)The surface-backscattering strength is calculated according to Rayleigh theory for surface excursions much smaller than the sound wavelength. By taking into account of self-shadowing and modulation of grazing angles, the ... -
Some ray and intensity solutions in the complex plane
(NATO. SACLANTCEN, 1974/02)This paper presents a method to test range-dependent ray-tracing programs. The method is based on complex-function theory. From an analytic function that has a zero point at the emitter, expressions for sound speed, ray ... -
Intensity calculations along a single ray
(NATO. SACLANTCEN, 1974/02)A method is presented for the calculation of sound intensity using only one ray. The sound-velocity profile is assumed to be continuous up to the second derivative and it is supposed that the ray equations are solved ... -
The wave equation in a medium with a time-dependent boundary
(NATO. SACLANTCEN, 1974/02)It is shown that the Helmholtz equation is not exactly correct for a medium with a time-dependent boundary. The equation can be used with very good approximation when the time-derivative of the surface elevation is much ... -
Acoustical characteristics of the sea floor: experimental techniques and some examples from the Mediterranean Sea
(NATO. SACLANTCEN, 1974/11)The acoustical properties of the sea floor are primarily determined by the physical properties of the sediments, layering in the sediments, and the roughness of the bottom and sub-bottom. Over the last decade many cores ... -
Ocean-basin reverberation from large underwater explosions: part 2: computer model for reverberation
(NATO. SACLANTCEN, 1975/10)Following detonation of an underwater explosion, sound reverberates from the ocean surface and bottom and from scatterers within the medium. In addition, the boundaries of the ocean basin and obstructions within it, such ... -
Gas bubbles in the sea: a review and model proposals
(NATO. SACLANTCEN, 1975/10)The literature pertaining to both free bubbles (pt 1) and bubbles associated with fish anotomy (pt 2) is reviewed with particular emphasis on their distributions in the sea and influencing factors. An attempt is made to ... -
Low-frequency acoustic measurements in a shallow-water area with a rough sea surface
(NATO. SACLANTCEN, 1975/10)Surface wave spectra have been measured in the North Sea simultaneously with acoustic investigations using explosive and CW sources. The goal of these experiments was to determine the influence of surface waves to low-frequency ... -
Acoustical probing for microbubbles at sea
(NATO. SACLANTCEN, 1975/10)Free gas bubbles have been indicted for many physical processes at sea including: scavenging detritus and chemicals from the ocean volume; generating droplets whose salts affect thunderstorm activity over the sea; providing ... -
A wave-theoretic method for estimating the effects of internal tides on acoustic wave transmission
(NATO. SACLANTCEN, 1975/10)The effect of the first mode semidiurnal internal tide on a ducttype sound speed profile was approximated by varying the minimum velocity of the parabolic profile in a sinusoidal fashion with a period of 12.42 hours. The ... -
Random temperature structure as a factor in long-range propagation
(NATO. SACLANTCEN, 1975/10)A statistical description of horizontal thermal microstructure in anosotropic turbulence is developed for application with an existing acoustic propagation theory. The model predicts a temperature power density spectrum ... -
Surface wave spectra
(NATO. SACLANTCEN, 1975/10)A classification is made of the different types of wave elevation spectra namely lD time spectra, lD spatial spectra, 2D spatial spectra and 3D space-time spectra. Relations with simple single parameter measures of surface ...